VNTR polymorphorism

I am a new user of GDBWWW. I have recently cloned a cDNA
fragment which contains about 200 bp region of CAG and
CAA repeat. I would like to know whether this CAG
trinucleotide repeat is highly variable and if it corresponds
to a polymorphorism locus in the GDB database. Can I
search the database with my sequence? Where can I get
more detailed information about how to use the GDB and
what kind results I can get from the database?